Printing press



June 17, 1941. J 5 ROGQWSK] 2,246,077

PRINTING PRESS Filed Dec. 18, 1939 John 5. R0 060.51%!) VENTOR.

15 ATTORNEY.

Patented June 17, 1941 PRINTING PRESS John S. Rogowski, Chicago, Ill.,assignor of onethird to Saul Kahn and one-third to Helen Kahn, both ofChicago, Ill.

Application December 18, 1939, Serial No. 309,882

Claims.

This invention relates to the art of printing, and while it is ofgeneral application, it is more particularly concerned with offsetprinting, the

principal object being the provision of means for preventing slippagebetween the plate and a tractionally interdriven form roller adapted totransfer ink onto the plate.

Viewed from another-aspect, it is a principal object of the invention toprovide, in combination with a plate cylinder and inking roller adaptedto be frictionally driven with the plate on the cylinder, a plate etchedor otherwise formed so as to have a recessed portion surrounded by aborder, with the copy disposed in the recessed portion and theink-receiving surfaces of the copy situated at the same level or in thesame plane with the surfaces oftheborder portion, particularly thoseparts thereof which extend in a direction circumferentially of the platecylinider, there being tractional rolling engagement between certainborder portions and corresponding parts of the next inking roller, andmeans for preventing transfer of ink to the traction surfaces.

A further object is the combination with a plate cylinder, a form rolleradapted to be frictionally driven against a plate on said cylinder, anda series of at least two other peripherally driven rollers fortransferring ink onto the inking roller, of means for preventingslippage between the inking roller and plate, which comprises theprovision of a plate having friction drive surface portions extending ina direction circumferentially of the plate cylinder and flanking arecessed portion in which the copy is etched, the ink receiving surfacesof said copy being situated at the same level as said friction drivesurfaces, and that one of the ink transferring rollers which bearsagainst said inking roller having its peripheral contact surfaceportions of shorter length than said inking roller wherebyto leaveuninked areas adjacent the axial ends of the latter of an extentadequate to prevent transfer of any ink to the friction drive surface ofthe plate.

Viewed from still another aspect, it is an object of the invention toprovide, in combination with a plate cylinder, a plate having frictiondrive surfaces formed integrally at its ends corresponding to the axialends of the plate cylinder and extending in a directioncircumferentially of the latter, and an inking roller bearing againstsaid plate and said friction drive surfaces, and another inktransferring roller bearing against said inking roller and havingreduced peripheral surface portions at its axial ends, said surfaceportions being of an extent in an axial direction at least equal to thewidth in the same direction of said friction drive surface on the plate,whereby to prevent the transfer of ink onto said friction drive surfacesand obviate slippage.

Other objects, advantages and novel aspects of the invention reside incertain details of construction as well as the cooperative relationshipof the embodiment described hereinafter in view of the annexed drawing,in which:

Fig. 1 is a perspective view of one form of roller arrangement in anofi'set press and in which arrangement the invention has beenincorporated;

Fig. 2 is a diagrammatic illustration of the roller arrangement of Fig.1;

Fig. 3 is a plan view of the novel plate;

Fig. 4 is a cross section through the plate along line 44;

Fig. 5 is an enlarged fragmentary detail of the rolling engagementbetween the ends of the riding and form rollers.

For purposes of illustration, the roller assembly employed in offsetprinting has been shown in Fig. 1, which arrangement includes an inkingdrum or roller l0 adapted to receive ink from a source of supply (notshown) and rotated by the power drive means of the press in thecustomary manner, preferably through a connection with the platecylinder. This inking drum, in addition to its rotary movement iscustomarily oscillated along its axis by means of a cam drive indicatedat H, the purpose being to assure a uniform and positive distribution ofthe ink to the other rollers of the series.

In accordance with the usual practice in offset printing, ink istransferred through a series of rollers onto a zinc plate l2 which isetched with the copy l2a. The plate is placed on a plate cylinder I3 andclamped in position as at l3a (Fig. 2), the cylinder being rotated toeffect transfer of ink from the system of rollers onto the copy, whichink is in turn transferred onto the surface of an offset roller It inconformity with the copy I 2a and indicated at I2b on the offset roller.

Means for transferring ink from a source of supply onto the zinc orplate, includes the provi sion of a' system of serially arranged rollersincluding the inking drum Iii, an intermediate transferring roller l5,and another intermediate transferring roller 16 known as a rider, whichin turn bears against the actual inking roller I! known as a formroller- As a result of the serial peripheral rolling engagement betweenthe rollers of the system, it will be evident that ink will betransferred from the drum ii) onto the copy I20. on the plate, when theseveral rollers are jointly driven.

Referring to Fig. 2, a driving arrangement for certain of the rollers,customarily employed in this type of press, includes the provision of amaster driving gear diagrammatically indicated at 20 (not seen in theother figures) and which meshes with a driving gear on the inking drumI0, a driving gear on the rider I6, and also a driving gear on the platecylinder I3. In the diagram of Fig. 2, the roller assembly has beenduplicated in accordance with actual practice, and it will be observedthat of the series of rollers; the intermediate roller I and the formroller I'I have no positive driving connection with the master gear 20,but rely upon frictional engagement with the riding roller I6, theinking drum, and the plate cylinder for their driving power.

It is highly important to assure proper distribution of the ink on thecopy or zinc etching, andlthissis best accomplished by having the formroller. I-I frictionally driven with the-plate cylinder and moreparticularly with the surface of the plate thereon;-however, in order:to employ such'afriction drive, it is also essential that all slippagebetween .the form roller H and theplate be wholly eliminated;

In accordance with prior practice, it was customary to spray with wateror moisten portions of the frictionally interdriven roller members from:which it was desired toexclude ink, such inksof necessitybeingwater-insoluble, particles of: waten lodging: in the grain.orcrevices in the plate substantially below the printing surface thereofso as not to interfere with the frictional drive; However, a: great dealof offset printing must be done with water-soluble inks, and it istherefore: impossible to resort to such a spraying or: moisteningexpediency, since the same would be ineffective and moreover wouldintroduce the seriousdanger of running of colors ofi margin or register.

The, present invention therefore has as its object the provision of arelatively simple and inexpensive. means for preventing such slippageregardless; of the natureof the ink used, said meanstincluding: theprovisionof a plate I2 (Fig. 3) which. has integrally formed frictiondrive surfaces, the plate being recessed as at I8 in the regionssurrounding the copy I2a and in a manner which will leave a substantialborder I9 with frictional drive surfaces I901; at opposite sides of theplate and extending in a direction of the circumference 'of' the platecylinder;

The plate may be made in the foregoing'form eitherby. routing; gougingor etching'out the surpluszmaterialaround'the copy within the borderportions; Itis important to observe in Fig. 4, particularly, that thedepth of the border I911, and the copy. I2a.is'substantial1y the same,so that the ink'receiving surface portions of the copy I2a,mother-terms, lie at the'same level or in .the same plane asthefrictionsurface portions of the border parts ISa, the reason for which willappear hereinafter.

Theinvention is completed by providing on the riding roller I6peripherally reduced surface portions I611. at the ends thereof, thesesurface portionsiextending in an axial direction at least a distanceequal to the'width, in the same direction, of? the. frictional drivesurfaces I9a. In consequence ofithis' arrangement, it will be evidentthat no ink will be transferred to the correspondingly positioned endportions. I'Ia. on the form roller,

thelatter surface portions. being those which are,

frictionally engaged with the surface portions I9a on the plate so thatink will be excluded from the latter surface portions with a consequentminimizing of the danger of slippage, particularly as it might resultfrom the driving engagement of inked or moistened surfaces.

It should be pointed out that the riding roller I6 is usually oscillatedin the same manner as the ink drum I0, and therefore means is providedfor preventing the transfer of ink onto the traction surface Ila as aresult of such oscillation, this means comprising the provision on theform roller I! and between the traction surfaces I'Ia and theintervening peripheral portions of the roller, of peripherallyreducedportions I'Ib (Fig. 5 particularly) in the nature of grooves or channelsof shorter radius than the adjoining peripheral surface portions of awidth measured in an axial direction adequate to permit axialdisplacement or oscillation of the roller I6 so that the main peripheralmargin thereof at thejuncture with the reduced portions Ilia will not;be shifted.onto the traction, surfaces I'Ia.

An added advantage of this latter arrangement resides in the fact thateven. though theriding roller- Ifi maybe disconnected from itsoscillating means, as is sometimes desirable-in offset printing,.therewill be no danger of ink creeping onto any part of the traction-surfaceI'Ia of the form rollervshould-the press be continuously driven onabigrun.

Rollers I5.I-1. and the plate cylinder I3"constitute a plurality ofperipherally rolling drums or members arranged in a series, the riderbeing' regarded as-the first roller and being one of the outer rollerswith respect to an intermediate roller III, and the plate, cylinderI3wconstituting;

a. third outer roller on-the opposite side of the intermediate rollerin, the series.

In the application-and.operation of the present invention asapplied to,the type of press described, the new form'of plate shown, for example inFig. 3, islaid onto the plate cylinder I3 and attached-as at I-3a inthecustomary manner. Assuming the riding'roller Ifi to be provided With thereduced and portions heretofore described, and the. oscillatorydriveforthis roller to have beendisconnected,.it will be apparentthat uponrotation of.- the system-of rollers and the cylinder, ink will betransferred-from the drum I0? to the intermediate roller I5- and thencewall but the reduced or receded surface portions IBa' of, the riding;roller, with a consequent transfer ofthe inkto thecorresponding-surfaceportions of the formroller I], there being'an absence of ink on the endportion Ila of the formroller and-a consequent absence of ink from thefrictional or tractional drive surfaces Ifia on the circumferentiallyextending border portions of the etched plate. Avery large number ofimpressions can be run without any likelihood of ink working from thepositively inked: portions of the form roller onto the uninked portionsIla, thereof, owing to the reduced parts IBa, Ill);

Thevarious advantages andobjects of themvention may be accomplished bymodifications of the particular embodiment specifically describedherein, and it is intended that the appended claims shall include'all:equivalent arrangements fairly. coming within their call.

Having thus described my invention, what I claim as new and desire toprotect by Letters Patent is:

1. Ina printingpress or the like including an inkreceiving: cylinder.having frictional driving engagement with a form roller, a riding rollerperipherally contacting the form roller and an intermediate roller whichin turn peripherally contacts an inking drum, said drum, rollers, andink receiving cylinder being of substantially the same length and saidinking drum being supplied with ink for transfer through the interveningrollers onto said ink receiving cylinder, means for preventing slippagebetween the frictionally driven form roller and cylinder which comprisesthe provision of a riding roller of shorter length than saidintermediate and form rollers whereby to prevent transfer of ink tothose end portions of the form roller disposed beyond the ends of theshorter riding roller with a consequent absence of ink at thecorresponding ends of said ink receiving cylinder to provide uninkedperipheral areas on the form roller and ink receiving cylinder toimprove the frictional contact between said uninked surfaces.

2. In a device of the class described including a cylinder adapted toreceive ink on its periphery, and a series of at least three inktransferring rollers including a first, an intermediate, and an outerroller, said outer roller being supplied with ink for transfer to theother rollers, said first roller being driven through frictional contactwith said cylinder, said intermediate roller having receded peripheralsurface portions of uniformly lesser radius than other surface portionsthereof and which are out of contact with the cylinder and intermediateroller whereby no ink will be taken fromthe latter on said recededportions and no ink will be transferred to the surface portions of saidouter roller which are opposite the receded surface portions, with aresulting absence of ink on corresponding portions of said cylinderwhereby uninked peripheral driving surfaces are provided on said outerroller and cylinder to reduce slippage between the same.

3. In a device of the class described, a system of inking and inkedrollers including at least four rollers arranged in serial peripheralcontact for rotation together, at least the last two rollers of theseries being frictionally driven, one from another, the outermost rollerof the remaining two of the series being adapted to receive ink from asupply source, means for reducing slippage between the frictionallydriven rollers, comprising the provision of uniformly inset peripheralsurface portions on the roller engaging said outermost roller and whichare out of contact with the latter so as to receive no ink therefrom andwhich inset portions are thereby incapable of transferring ink ontocorrespondingly positioned portions of said last two frictionally drivenrollers.

4. In a device of the class described, the combination of a plurality ofat least three rollers arranged for peripheral rolling engagement inseries, a first roller of said series being adapted to have itsperipheral surface portions supplied with ink, said ink beingtransferred to the next adjacent or second roller of the series inrolling action, the ink in turn being transferred from said secondroller to the third roller of the series, said second and third rollersbeing arranged for tractional driving engagement at axially spacedpoints, and means for preventing the transfer of ink onto the tractionportions of said rollers, said means comprising the provision of axiallyspaced peripherally reduced portions on said first roller which are ofshorter radius than the surface portions intervening therebetween and inconsequence out of contacting engagement with the correspondinglyopposite surface portions on the next adjacent or second roller wherebyno ink will be transferred tosaid correspondingly adjacent surfaceportions, the latter being tractionally engaged with correspondingsurface portions on the third roller, said second roller being providedwith peripherally reduced surface portions positioned substantiallyopposite the juncture of said peripherally reduced portions with saidintervening portion on the first roller, whereby to prevent the creepageof ink onto the traction surface of said second roller from theintervening surface portions on the latter and also to permit axialoscillation of said first roller an amount depending on the extent in anaxial direction of the reduced portions on said first roller.

5. In a series of at least three peripherally rolling inked and inkingrollers, at least two of which are in tractional driving engagement,means for preventing the transfer of ink to the traction surfaces whichcomprises the provision of peripherally reduced inking surface portionson a first one of said rollers whereby ink is prevented from passingonto correspondingly opposite portions of the second and third rollers,said second roller having circumferentially grooved portions disposedapproximately opposite the juncture of the reduced and normal surfaceportions of the first roller to prevent creepage of ink onto thenormally uninked portion of the second roller and also to permit axialdisplacement of said second roller distances depending on the width ofsaid grooved portions, and means for inking the normal unreduced surfaceportions of the first roller.

JOHN S. ROGOWSKI.

